okay so i recently installed my avic-d3 and my two 13ov.2 d4 (12") from elemental design. How do i tune my d3 so that it blend with my subs. Because my bass had drowned out lil wayne when he was rapping. So how do i go about to do this?

Two 12" subs is going to drown out anything played over stereo speakers run off the D3's amp. If you want to run that much bass, you would have to use an external amplifier to get enough volume to have the stereo speaker volume output match the level of the subs.

So either:

1 - Amp the stereo speakers

or

2 - Turn down the bass

Or 3 get some tweeters.

Yep, definitely going to have to get a multichannel amp for your car speakers. I have a Memphis 10" with a mono sub driving it and a 4 channel amp driving my memphis front, rear door and tweeter speakers.